MLK-14393 i2c: imx-lpi2c: directly retrun ISR when detect a NACK

A NACK flag in ISR means i2c bus error. In such codition,
there is no need to do read/write operation. It's better
to return ISR directly and then stop i2c transfer.

Signed-off-by: Gao Pan <pandy.gao@nxp.com>
(cherry-pick from 839d59e48b6fdbd882776a48a88ce26ff14d8b86)

diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index e5ea0a2..35e9728 100644 (file)
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -520,15 +520,17 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
        lpi2c_imx_intctrl(lpi2c_imx, 0);
        temp = readl(lpi2c_imx->base + LPI2C_MSR);
 
+       if (temp & MSR_NDF) {
+               complete(&lpi2c_imx->complete);
+               goto ret;
+       }
+
        if (temp & MSR_RDF)
                lpi2c_imx_read_rxfifo(lpi2c_imx);
-
-       if (temp & MSR_TDF)
+       else if (temp & MSR_TDF)
                lpi2c_imx_write_txfifo(lpi2c_imx);
 
-       if (temp & MSR_NDF)
-               complete(&lpi2c_imx->complete);
-
+ret:
        return IRQ_HANDLED;
 }